Fixierungsvorrichtung zur Fixierung eines Marknagels, insbesondere eines Marknagels zur Versorgung einer Fraktur eines Knochens, mit einer Spannhülse (1), die ein Greifende zum Greifen eines Endstücks (30) eines Marknagels (50) umfasst, wobei die Spannhülse (1) an dem Greifende geschlitzt ist.The device has a clamping sleeve (1) comprising a gripping end for gripping an end part of an intramedullary nail, where the clamping sleeve is slotted at the gripping end. A receiving pipe partly surrounds the clamping sleeve. The clamping sleeve is detachably attached at an objective equipment that is provided with the receiving pipe and a clamping screw for clamping the clamping sleeve. The clamping sleeve is provided with an anti-twist plate for preventing rotation of the end part opposite to the clamping sleeve. The anti-twist plate comprises a cam (10) and/or a recess. An independent claim is also included for an intramedullary nail for treating fracture of a long bone.